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Topic: 5DMkIII AF performance at f/8 (Read 8227 times)

I'm wondering about the AF performance of this body at f/8, specifically using the Canon EF 100-400mm L IS USM + 1.4x Extender II (=140-560 f/6.3-8).

I've never used an extender with my 100-400 before, but because I'll be losing the crop factor of the 7D, I am a little concerned re the impact on AF and image quality for those times I need the extended reach.

I've used it with the 300f4L and 2x mk3its quite slow but useable for stuff that is not fast moving, say a slow gliding bird it will track ok but for something moving fast it will fail.As for shooting static stuff AF aquisition is not too bad

Thanks for commenting, I guess this is in line with my expectations. So using the 1.4TC on my 100-400 will be an 'emergency only' solution as far as AF goes (I'm not too excited about a 7/8 max aperture anyway)...

I have noticed the Sigma 120-300mm F2.8 DG OS HSM | S. If that has decent performance with a 2x TC, and works with the Canon 1.4TC as well, that might be something to consider getting later on if I really find I need more reach. I'm hesitant to buy tele-primes; I like the flexibility of a zoom for distant subjects.

Thanks for commenting, I guess this is in line with my expectations. So using the 1.4TC on my 100-400 will be an 'emergency only' solution as far as AF goes (I'm not too excited about a 7/8 max aperture anyway)...

I have noticed the Sigma 120-300mm F2.8 DG OS HSM | S. If that has decent performance with a 2x TC, and works with the Canon 1.4TC as well, that might be something to consider getting later on if I really find I need more reach. I'm hesitant to buy tele-primes; I like the flexibility of a zoom for distant subjects.

I like the zoom flexibility too. I suspect you'll be disappointed with the sharpness of the 100-400 with a TC, at least at the long end. The Sigma has interested me for a while, but from what some Sigma critics have said, it's not all that sharp with TC's...and I don't think it can use Canon TC's. Could be wrong, but I know their other lenses won't work with Canon TC's.

I've never used an extender with my 100-400 before, but because I'll be losing the crop factor of the 7D, I am a little concerned re the impact on AF and image quality for those times I need the extended reach.

The sad truth about tele zooms + tc is that the tc multiplies the lens' weakness at the long end, this is reported to be even worse on the older 100-400L vs. the newer 70-300L ... you should consider if it's really worth the hassle.

For me a tc is "nice to have" for zooming in spectacular static sunsets, but for everything else the slower af performance and iq loss tells you the reason why there are fast tele primes around that are actually meant and designed to be used with a tc and don't just happen to work with it.

I would suggest that you are better off sticking to the 7D with the 100-400 rather than shooting with the FF + 100-400 + 1.4TC.

I tried this combo and it worked reasonably in good light. That said, if you are looking for pixel level sharpness, forget it. Also, if you are shooting birds in the trees, you lose AF, hit a max aperture of f/8 and in dark foliage, are at ever increasing ISOs to render the images unusable.

Personally, I would prefer to use the extenders only with a f/2.8 or a f/4 lens.

I would suggest that you are better off sticking to the 7D with the 100-400 rather than shooting with the FF + 100-400 + 1.4TC.

I tried this combo and it worked reasonably in good light. That said, if you are looking for pixel level sharpness, forget it. Also, if you are shooting birds in the trees, you lose AF, hit a max aperture of f/8 and in dark foliage, are at ever increasing ISOs to render the images unusable.

Personally, I would prefer to use the extenders only with a f/2.8 or a f/4 lens.

I never used the 1.4 with the 100-400, in fact I never used the 1. with the 7D much. It just never worked much for me.

I do use the 100-400 with the 5D3 and find it better than with the 7D. I certainly don't miss the "crop factor", its so much better I get more detail anyway. I also use that lens with the 1Dx and while its not top quality its a great versatile lens.

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If you debate with a fool onlookers can find it VERY difficult to tell the difference.

I would suggest that you are better off sticking to the 7D with the 100-400 rather than shooting with the FF + 100-400 + 1.4TC.

I tried this combo and it worked reasonably in good light. That said, if you are looking for pixel level sharpness, forget it. Also, if you are shooting birds in the trees, you lose AF, hit a max aperture of f/8 and in dark foliage, are at ever increasing ISOs to render the images unusable.

Personally, I would prefer to use the extenders only with a f/2.8 or a f/4 lens.

I never used the 1.4 with the 100-400, in fact I never used the 1. with the 7D much. It just never worked much for me.

I do use the 100-400 with the 5D3 and find it better than with the 7D. I certainly don't miss the "crop factor", its so much better I get more detail anyway. I also use that lens with the 1Dx and while its not top quality its a great versatile lens.

So the question is if I'm satisfied with 400 mm on full frame - I think I'll manage. Strangely I've been moving more toward 'wide angle' in the past year, even in the tele side of things - I like to get a little more in the frame

As far as relative sharpness goes, I do expect the 100-400 to give better results on full frame, especially since I usually shoot at a resolution of around 10 megapixels on average (using mraw). This does mean that if I need the extra reach it is probably better to shoot in full raw and crop in post. I guess I can live with that...

I would suggest that you are better off sticking to the 7D with the 100-400 rather than shooting with the FF + 100-400 + 1.4TC.

I tried this combo and it worked reasonably in good light. That said, if you are looking for pixel level sharpness, forget it. Also, if you are shooting birds in the trees, you lose AF, hit a max aperture of f/8 and in dark foliage, are at ever increasing ISOs to render the images unusable.

Personally, I would prefer to use the extenders only with a f/2.8 or a f/4 lens.

I never used the 1.4 with the 100-400, in fact I never used the 1. with the 7D much. It just never worked much for me.

I do use the 100-400 with the 5D3 and find it better than with the 7D. I certainly don't miss the "crop factor", its so much better I get more detail anyway. I also use that lens with the 1Dx and while its not top quality its a great versatile lens.

So the question is if I'm satisfied with 400 mm on full frame - I think I'll manage. Strangely I've been moving more toward 'wide angle' in the past year, even in the tele side of things - I like to get a little more in the frame

As far as relative sharpness goes, I do expect the 100-400 to give better results on full frame, especially since I usually shoot at a resolution of around 10 megapixels on average (using mraw). This does mean that if I need the extra reach it is probably better to shoot in full raw and crop in post. I guess I can live with that...

If you are only shooting at 10 MP, how can you even mingle with a gear-crazy crowd on here that is constantly talking about getting ultimate sharpness and crop flexibility? You're getting neither if you shoot critical shots in MRAW.

The only reason I've shot in MRAW or smaller jpegs, is when I know I can't use the full resolution. That's either when the image is just not important...or it's shot through glass (especially through a windshield of a moving car)...or if it's both not very important and also employing ISO 51,000...or above.

I find myself most often shooting the casual stuff at full resolution but as either high or low quality jpeg...especially anything that does not have a lot of contrast or dynamic range to the image. If I want the DR but still don't want the pixels, that's when I select the smaller RAW resolution file.

It's kind of funny just what the 6D is capable of, when "only" shooting jpegs...

Here is a picture of mine on the birds thread. There are more. Take a look.http://www.canonrumors.com/forum/index.php?topic=1280.msg344225#msg344225Mind you, the ISO is 5000! You can blame the f8 for that. But then it is either that or be happy with 400mm...If there is light the AF is ok. If there are many leaves obscuring the subject one has a problem. Oh! Use the focus limiter...

Here is a picture of mine on the birds thread. There are more. Take a look.http://www.canonrumors.com/forum/index.php?topic=1280.msg344225#msg344225Mind you, the ISO is 5000! You can blame the f8 for that. But then it is either that or be happy with 400mm...If there is light the AF is ok. If there are many leaves obscuring the subject one has a problem. Oh! Use the focus limiter...

Thanks for sharing the photo, rpt! Not bad for this combination I would say. Was that shot with a 1.4 MkII or III? I got my 5D3 today, and am looking forward to using it (a lot)

If you are only shooting at 10 MP, how can you even mingle with a gear-crazy crowd on here that is constantly talking about getting ultimate sharpness and crop flexibility? You're getting neither if you shoot critical shots in MRAW.